I just bought a 1996 Thompson Calae 1800 open bow that had its 4.3L Merc changed to a 5.7L Merc 2 years ago. It has an alpha one outdrive with a 1.62 Gear ratio and a 21 pitch prop. The problem im having is that I trim down all the way to take off, open it all the way to WOT, and the boat takes off and planes right out with out me triming up at all. With the trim all the way down the boat runs around 3800 Rpms and if I just tap the trim up a nudge it will hit 3900 RPMS and cruise really good. If i try to trim up any more the rpms will increase put i lose speed and the prop sounds like it sucking air. Also at times that I leave it wide open the engine will make a noise like it has a rev limiter or governor on it and I have to back off a bit to get it to stop. The guy I bought it from told me he had a 19 pitch on there first and it would always sound like a governor was kicking in so he went with the bigger prop which reduced it but not all the way. I know the merc 350 should run near 4400 to 4800 WOT which mine is not hitting which im afraid it will end up hurting the motor running at 3900 rpms. Im not really sure what 5.7 it has other than the top cover says 5.7L Thundebolt V LX on it but the previous owner thinks that they just but that cover on it. I know it is a chevy 350 and I saw Bravo stamped somewhere on the motor but other than that i dont know how to tell what they put in there. Any ideas on what I should do???
